1. Field of the Invention
The present invention relates generally to an antenna, and more particularly to a dual-band dipole antenna.
2. Description of the Prior Art
In recent years, Wireless Local Area Network (WLAN) products under IEEE 802.11a/b/g standards, such as WLAN cards for computers are gaining popularity in wireless communication market. Wherein, IEEE 802.11b/g standard is suitable for working at 2.4–2.5 GHz frequency band, while IEEE 802.11a standard is suitable for working at 5–6 GHz frequency band. Many of said WLAN products want to be use under both IEEE 802.11a and IEEE 802.11b/g standard benefit from dual-band antennas.
For achieving dual-band effect, a dual-band dipole antenna is one of the most mature dual-band antennas in both design and manufacture.
A conventional dual-band dipole antenna is disclosed in U.S. Pat. No. 6,421,024 B1. Referring to FIG. 1, said conventional dual-band dipole antenna comprises a first antenna having two lower dipole halves 60 and 61, and a second antenna having two higher dipole halves 70 and 71. Each of the dipole halves 60, 61, 70 and 71 is formed from an electrically conductive cylindrical tube. Wherein, the lower dipole halves 60 and 61 are jointly operated at a lower frequency band range, while the higher dipole halves 70 and 71 are jointly operated at a higher frequency band range. However, the four dipole halves of the conventional dual-band dipole antenna are all made of metal material, which results in higher cost.
Hence, in this art, a dual-band dipole antenna with low cost to overcome the above-mentioned disadvantages of the prior art will be described in detail in the following embodiments.